In the manufacturing process of semiconductor devices, large amounts of material are deposited onto wafers. In the course of depositing large amounts of material onto a wafer, the material is also deposited onto a bevel portion which is the circumferential edge portion of the wafer. It is not necessary for the semiconductor devices to have such a film deposited onto the bevel portion. In addition, in the course of the manufacturing process, the film deposited onto the bevel portion of the wafer may be peeled off and may contaminate the surface of the wafer. In such a case, the product yield is decreased. For this reason, the film deposited onto the bevel portion is removed by a process such as polishing.